This application corresponds to Japanese Patent Application No. 9-194872, filed on Jul. 3, 1997, which is hereby incorporated by reference in its entirety.
The present invention relates to an apparatus and method for aligning a multiplicity of chip parts in a row and delivering the chip parts in sequence.
Known part-aligning apparatus of the above-mentioned kind include bulk feeders and vibrating ball feeders. Bulk feeders are roughly classified into pneumatically driven bridge-breaking type feeders and bridge-breaking type feeders which use an upward-thrusting pin in operation. In the case of the pneumatically driven type of feeder, it is difficult to adjust the amount and direction of airflow. In the case of the upward-thrusting pin type of feeder, whenever an operation is performed, the pin impacts the parts and so the parts tend to be easily scratched or damaged. In both types, every chip part is forced toward a funnel-like exit. Therefore, if a bridge-breaking operation is performed once, the bridge may be immediately restored. As a consequence, the efficiency at which parts are aligned is low. In the case of the vibrating ball type of feeder, bridges are not readily formed. However, this equipment is expensive. Also, unwanted vibration is easily transmitted to other apparatus. Furthermore, a large space is required for this type of equipment.
A part-aligning apparatus free of these problems is proposed in Japanese Unexamined Patent Publication No. 143164/1996. This apparatus comprises a cylindrical stocker for holding chip parts, an annular body disposed on the outer surface of the outer curved wall of the stocker, and a rotary disk having an annular indexing portion. This indexing portion is rotatably disposed in the gap between the outer curved wall of the stocker and the inner surface of the annular body. The indexing portion has a plurality of chip-holding recesses for individually seizing the chip parts. A chip discharge hole in communication with a chip storage portion is formed near the bottom of the outer wall of the stocker and in the path over which the chip-holding recesses are moved. In this case, movement is provided only by rotary motion, and accordingly, it is easier to make an adjustment. The chip parts are damaged less. In addition, the apparatus can be easily built to have a smaller size.
However, the above-described part-aligning apparatus requires at least the stocker, the annular body, and the rotary disk. Therefore, this apparatus is complex in structure and often breaks down. It is necessary that the rotary disk has chip-holding recesses arranged circumferentially, the recesses conforming to the shapes of the individual chip parts. In order to align minature chip parts having a length of about 1 mm long, the chip-holding recesses must be processed in correspondingly small size. Hence, the apparatus is very complex in structure and laborious to machine, thus increasing the cost.
The chip parts are held in series (e.g., the chips are held adjacent to each other in a line) by the chip-holding recesses in the indexing portion of the rotary disk. As the disk turns, the chip parts are forced toward a chute. Therefore, if the chute becomes clogged or overflows with chip parts for some reason, a chip part subsequently fed in will be caught in the chute. As a result, the chip part may be damaged or the apparatus itself may break down. At this time, therefore, it is necessary to quickly stop the rotary disk using a xe2x80x9cfull occupationxe2x80x9d sensor.
It is an object of the present invention to provide a part-aligning apparatus that is simple in structure, less damaging to chip parts to be aligned, and functions well even if the chip discharge passage becomes clogged or overflows.
It is another object of the invention to provide a method of aligning chip parts without being affected by clogging of the chip discharge passage or by overflow of the chute such that the chip parts are less damaged than heretofore.
The above objects are achieved in accordance with the teachings of the invention by an apparatus comprising: a part-holding chamber for accommodating a multiplicity of chip parts; a chute groove formed at least in the inner surface of the bottom of the part-holding chamber and acting to orient the chip parts in a given direction and to cause the chip parts to slide downward; a gate port formed at the lower end of the chute groove for passing the chip parts in series (e.g., one by one), wherein the chip parts slide downward in a given orientation along the chute groove; a discharge passage for aligning the chip parts which have passed through the gate port in a line for discharging; and a rotary impeller having blades rotatably held in the part-holding chamber. The blades have front end portions passing over the gate port. The blades of the impeller are rotated to displace any chip part halted in an abnormal orientation in the gate port toward a direction different from a direction in which the chip parts are discharged, thus preventing the gate port from clogging.
The chip parts introduced into the part-holding chamber are collected on the inner surface of the bottom of the part-holding chamber by the force of gravity, which causes the chips parts to fall into the chute groove. The chute groove has a width which allows the chip parts to fall into the chute groove in a given orientation. For example, where a chip part has a rectangular prism shape, e.g., the length is greater than the width and the height, if the width of the chute groove is set slightly larger than the width and the height of the chip parts, the chute groove can align the chip part in the longitudinal direction of the chip part. Each chip part falling into the chute groove is slid downward by gravity and brought to the gate port. If the chip part is in a correct orientation (e.g., a laid-down orientation), the chip part passes through the gate port without difficulty. This chip part is then discharged into a discharge passage. However, if a chip part in an abnormal orientation (e.g., an elevated or upright orientation) reaches the gate port, the part clogs the port because it can not pass through the port in this orientation. Since the blades of the rotary impeller regularly pass over the gate port, the chip part stopped at the gate port is displaced in a direction different from the direction in which chip parts are discharged. The result is that the clogging chip part is removed from the gate port or at least knocked over to assume its normal orientation. This prevents the clogging. Hence, the chip parts arranged in back of the once-clogging chip part can be discharged through the gate port.
The chip part stopped at the gate port may be displaced in a direction that is opposite, or at an angle, to the discharge direction. Any direction may be adequate as long as the clogging can be prevented.
When a rotary impeller is rotated intermittently, the chip part stopped at the gate port can be laid down easily, thereby improving the clogging preventing effect.
When a guide surface for sliding the chip parts into the chute groove is formed on an inner surface of the part-holding chamber, the chip part slides smoothly into the chute groove, thus improving the efficiency of alignment. This guide surface may be an inclined surface, or a curved surface, as long as the chip part can be slided down to the chute groove smoothly by the guide surface.
When a part-holding chamber may be cylindrical space whose central axis is a horizontal axis, a chute groove is an arc-shaped groove formed on an inner surface of the cylindrical space, the discharge passage is formed substantially tangential to the arc-shaped chute groove, and the gate port is formed at the junction of the chute groove and the discharge passage, then the chip part moves smoothly from the chute groove into the discharge passage through the gate port. It is not limited to that the discharge passage is formed precisely tangential to the chute groove. The discharge passage may be inclined thereto.
In another exemplary embodiment of the invention, a plurality of chute grooves are formed in parallel in the inner surface of the part-holding chamber, and a gate port and discharge passage are formed at the lower end of each chute groove. In this case, chip parts are aligned with improved efficiency.
The present invention is suited for alignment of chip parts formed in a rectangular prism shape, e.g., where the length is greater than the vertical and lateral dimensions of the chip part. However, in addition to rectangular chip parts, the invention can be applied to align and deliver cubic chip parts and cylindrical chip parts.